The Structural Biology Facility provides: a) resources required for crystallographic structure determination, refinement and analysis, b) molecular graphics and computational support for structural biology, c) molecular graphics and computational support for structure-based drug discovery and d) highly specialized resources for macromolecular characterization related to structural biology. The Facility is essential for the research programs of investigators ofthe Cancer Center who are studying the relationship between macromolecular structure and function, or who are using macromolecular structure as the starting point for structure-based drug design. It is a unique resource at Northwestern University that capitalizes on the extensive expertise of a large group of users and the unique access to the synchrotron radiation X-ray source at Argonne National Laboratories. It also serves to nucleate the development of a local community with expertise in structural and computational biology. Such expertise will increasingly be called upon as the structures of more cancer related proteins become available. The Structural Biology Facility is located on both campuses of Northwestern University. It is based in the Department of Molecular Biosciences on the Evanston campus and in the Department of Molecular Pharmacology and Biological Chemistry in the Feinberg School of Medicine on the Chicago campus, and also at the Life Sciences Collaborative Access Team (LS-CAT) beam lines at Sector 21 of the Advanced Photon Source (APS). Dr. Alfonso Mondragon, a structural biologist at the Evanston Campus, directs the Facility. The Facility consists of three major components: 1) an outstation at the APS that is devoted to state of- the-art macromolecular crystallography, and, at both campuses, 2) automated facilities for setting up and visualizing crystallization experiments, and 3) computational facilities to support structural determination calculations, including NMR, crystallography and electron microscopy, computational drug-design, simulations and modeling efforts, including advanced graphical visualization and manipulation of models. The distributed nature ofthe facility reflects the means by which the data collection, computational, molecular visualization, and other scientific resources are networked, and thus integrated, for the structural biology research community at Northwestern. The Facility is continuously adapting to a changing environment During the last few years, it has modernized its entire computer infrastructure and increased significantly the number of crystallization robots and other modern tools for crystallography. The Facility plans to continue to grow and expand by adding more and better instruments, continue the upgrade/modernization ofthe existing equipment, and to incorporate new groups to its expanding user base.